Convergence /

Difficult choices for service providers

By Christine Perey
Network World, 01/21/02

When implementing a videoconferencing-over-IP service, a service provider must make difficult choices that affect interoperability, quality, scalability, security, functionality and the building cost.

LAN issues - A service provider may rely on the existing LAN connection to a meeting room or desktop, or it may require a dedicated connection between the client and service provider. When using a corporate network for local access, congestion and security issues beyond the service provider's control can cause usability and performance issues. The service provider must also designate a point of presence where the LAN and WAN internetwork. On the other hand, when a service provider requires the installation of dedicated services, costs go up, and functionality (such as the ability to access resources on the LAN during a conference, or to use the bandwidth for a data application when not using for video) may be compromised.

WAN issues - The selection of wide-area transport infrastructures and development of network operations centers go hand in hand. When a service provider chooses a single WAN for all videoconferencing traffic, then servers may be distributed strategically in the network. This can reduce the need for overprovisioning. When a single network is selected, a quality-of-service-guarantee mechanism can be implemented across all segments, increasing the reliability of QoS and offering the option of service-level agreements. Finally, negotiating bulk bandwidth agreements with a single provider may reduce costs.

When a company remains neutral to the wide-area infrastructure, some of those advantages may be compromised. However, this lets the service provider choose the transport method depending on the customer, day or type of application, according to the costs, availability and QoS. A multinetwork service platform may also be more complicated to manage and requires that operations be more central.

How we did it
Online interactive Buyer's Guide

Some companies choose to place their service platforms on the Internet. Disadvantages include security, stability and reliability (because traffic on the Internet fluctuates, and peaks are detrimental to real-time applications). But advantages are reach and cost. Anyone can reach the public Internet, and the cost is for access, not throughput.

Standards - For videoconferencing applications, the client has to capture and compress video and audio, and packetize the compressed data when placing it on an IP network. Many equipment manufacturers have adopted standards for video communications over IP (for example, H.323). But new standards (such as Session Initiation Protocol) are approaching and proprietary solutions persist. Proprietary solutions may take advantage of improved compression algorithms or be lighter in footprint.

If a service provider develops the service and client technologies as an integrated package, special features can be added or removed more quickly, depending on service agreements with customers. Designating the client application can also eliminate problems with supporting multiple software releases, conflicts with corporate network firewalls and other factors that could be outside the control of the service provider. In the majority of the cases where a private network service is offered, service providers expect the customer to purchase or already own client equipment that is compatible with the International Telecommunic ation Union protocols.

Software-only or hardware-accelerated clients - The customer's preferences determine if software applications on a multimedia PC with a Web camera are more appropriate than a hardware-accelerated appliance. The two extremes produce dramatically different experiences, primarily because the quality possible with hardware acceleration is considered more acceptable for group applications and most hardware-accelerated end points use a handheld remote to control the application. With a Web camera, you control the application via keyboard and mouse. Between these extremes, there are also standards-compliant 'all software' applications available.

Because of these and other considerations, no two service architectures are exactly alike. For our review, we separated those services that use the Internet for transport from those that manage the WAN services and guarantee QoS to customers through partnerships with bandwidth providers or by using their own networks.

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